Core drill



April 1950 A. F. PICKARD 2,503,561

CORE DRILL Filed Nov. 19, 1945 s Sheets-Sheet 1 I I0 to I 27 5---- Inventor-z $24 ALber't F Pickczrd.

Attorneys.

April 11, 1950 A. F. PICKARD 2,503,56

Attorneys.

A. F. PICKARD April 11, 1950 CORE DRILL Filed Nov. 19, 1945 o m m w m o s 1 s. a a n s. 4 k. M 2. 2 y fa w A 5 m\\ n\\\\\\ n ll e\mw r m 9 m IF m a lli. t I 3 w? m M A April 1 1950 CORE DRILL Filed Nov. 19, 1945 s Sheet t 4 rd k e nk m 1. H Q QA F 45 r e M m w AV 9 B n 3 3 3 /H\ 1| T11 Hm el \/I\ 1- 4 qJ AN .1 WM M April 11, 1950 A. F. PICKARD 6 CORE DRILL Filed Nov. 19, 1945 5 Sheets-Sheet 5 32 3e 20 Fig-16 I,

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Patented Apr. 11, 1950 CORE DRILL Albert F. Pickard, Minneapolis, Minn., assignor to E. J. Longyear Company, Minneapolis, Minn., a corporation of Delaware Application November 19, 1945, Serial No. 629,373

4 Claims.

This invention relates to an improved type of core barrel and drill signal device which is used for the recovery of core samples in exploratory drilling. In core drills the drill bit consists of an annular tube which is faced at the end with diamonds or other hard cutting material. As the bit rotates it grinds an annular groove in the direction of drilling, the ground material being washed away by a flow of water which is forced down through the tubular drill and carries the drilled residue upwardly outside the drill tube. The idea in core drilling is to save as much core as possible and to remove it periodically so as to determine the formation through which the drill is passing. One hundred percent of core recovery is the ideal operation but as a practical matter, 100% core recovery has seldom been obtained in broken or soft formations with equipment heretofore available.

In the rigid type of core barrel heretofore used, an inner tube is fastened by means of a suitable fitting inside the drill tube and serves to receive the core as it is produced. While drilling, the inner tube rotates with the outer or drill tube. A core lifter or bevel spring fits into a corresponding bevel in the bit and water travels in the direction of drilling between the rigid core barrel and the inside of the drill tube, passes over the face of the bit and washes away the cuttings which rise outside the drill tube to the surface. A part of the water is diverted and travels upwardly through the inside of the core barrel and out through top holes in the core barrel head to the exterior of the drill tube. The purpose of this latter flow of water is to carry or float the core upwardly as it breaks 01? on the natural seams in the rock. When the core is fractured it tends to jam in the core barrel and in the core lifter at the bottom of the core barrel. The tendency is to expand the lifter until it comes in contact with the walls of the bit. The bit being in rotation starts the core lifter to rotate and the blocked core likewise rotates causing grinding, from which juncture the entire core previously produced begins to rotate and grinds away on the bottom of the hole. In broken ground and in sticky formations such blocking occurs frequently with this type of core barrel; drilling progress is very slow and many bits are burned or stuck because a large percentage of the circulating water is allowed to release upwardly through the core barre] and out through the top holes thereof without passing across the face of the bit.

The grinding of the core which occurs to some 55 extent in practically all formations causes excessive wear on the diamonds or other abrasive cutting material in the face of the bit and in the metal of the bit, the drill tube and the core barrel, and in the rigid type core barrel, the core lifter, the shoulder of the tubular bit and the lower end of the core barrel are also subject to heavy wear due to the grinding of the core. This is due to the fact that when the core grinds it breaks into small particles which, however, are not as line as those produced by the cuttin edges of the bit during proper operation. Consequently, these somewhat larger particles do not clear so easily and produce excessive abrasion.

To overcome some of the coring difficulties of the rigid core barrel, manufacturers have, a number of years ago, developed what is known as the swivel type core barrel. In this type of arrangement the core barrel inner tube is hung on a set of ball bearings located in the lower end of the core barrel head. The core barrel inner tube hangs freely Within the tubular drill and is supposed to stand stationary as drilling progresses although it frequently rotates as hereinafter explained. When the core blocks or crushes in the bit the broken particles wedge outwardly, assume a larger outer diameter and pack into the core lifter which may be expanded until it hits the walls of the bit where it r0- tates with the bit and grinds the core.

It is very difiicult for a drill operator to tell when a bit is blocked when running with a swivel type barrel. Running on a blocked bit puts a heavy pressure on the core and in soft formations crushes and packs the core into the core barrel inner tube so that much time is lost in removing the core. In addition runnin 'on a blocked bit in hard formations. frequently crushes the bearings in the core barrel itself. Many blocks occur because the core barrel inner tu-be tends to creep around or rotate rather slowly. This causes pieces of the core to wear against one another making cuttings or chips which settle into the interstices between the roken core parts in the core barrel inner tube. A split core likewise has the effect of expanding the core lifter until it touches the rotating bit, thus causing the entire mass, i. e. previously recovered core, core lifter and core barrel inner tube, to rotate as a Whole and to grind against the bottom of the hole.

It is an object of the present invention to provide an improved core barrel capable of lengthening the average run and so constructed that no excessive pressure is applied to the core as it is received in the core barrel inner tube. It is also an object of the invention to provide an apparatus wherein the core is easily removed from the core barrel inner tube when it is withdrawn from the hole.

Further and more specific objects of the invention include the provision of improved types of core lifters adaptedto varyingformations and capable of being substituted one for the other as the formation changes; to provide a slotted core barrel inner tube constructed so that the core lifter acts to lock the inner tube of the core barrel to the core as itisproducedrandthus preclude rotation; and to provide a carefully balanced and designed core barrel assembly capable of gently receiving the softest cores and cores wherein there are many parting seams so that even a soft core in a soft or fractured formation is obtained nearly completely throughout the drilling operation.

It-isalso an object of the invention to provide an improved .core barrel inner tube capable of fitting within'a-fraction of an inch to the face of :thebit andcproviding an unobstructed recess to receive the core, thus increasing-the average length of the run ascompared withconventional core barrels of the prior art.

It is=alsoan object of the invention to provide an improvedcore barrel and signaling arrangement capable of .positively indicating to the operator whenthe core barrel is filled or if blocking occursyand to provide an apparatus capableof providing a flow of water across the face of the drill bit after the operators signal hasibeen given prior to' thev-stopping of the drill.

It is alsoanobject of the invention toprovide an improved core barrel which allows drainageof the tubular drill rod, thus eliminating a wet pull.

Other and further objects of thezinvention are those inherent in the apparatus herein illustrated-described and claimed.

The invention i illustrated with reference to the-drawings in which Figure 1 is an elevational view, partly in section, illustratin theoutside of the core drill and core lifterassembly;

Figure 2 is an elevational view, partly'in'section,-and partly-brokenaway, corresponding to Figure 1 illustrating the signaling device andthe core barrel assembly;

Figure'3--is an-enlarged viewshowing the lower end-of the drill-bit, the reaming shell'and core lifter and core barrel assembly;

Figures l, 4A,-5, 5A; 6, 6Aare a set of full scale views illustrating three operating conditions of the drill signal and core recovery device. The sheet carrying Figures 4, 5 and 6 should bearranged-above and in line with the sheet carrying Figures 4A, 5A and 6A;

Figure 7 is a full scale side elevational view of the drill bit which forms the lower extremityof the-apparatus shown in Figures 1-6;

Figure 8 is a sectional view taken along the lines B-8 of Figure 4 and illustrates a part of thefiuid passageway through the apparatus;

Figure 9 is a sectional view taken along the lines 9-9 of Figure 3 and illustrates the action of on form of the core lifter arrangement used in the present invention;

Figure 10 is a side elevational view of one part of the fluid valve arrangement separated from the remainder of the apparatus;

Figurell is a full size side sectional view showing one condition of operation which occurs when a broken formation is encountered;

Figure 12 is a separated view of one part of the apparatus and shows the form of core lifter illustrated in Figures 2, 3, 4A, 5A and 6A;

Figure 13 is a fragmentary side sectional view showing the lower end of the drill equipped with a second 'formof core lifter suitable for use in soft formations;

Figure 14 shows the same apparatus as in Figure 13 during a drilling operation as the drill .is progressing in the drilling direction;

Figure 15 corresponds to Figures 13 and 14 and illustrates the function of the apparatus as the core is pulled upwardly and shows the core broken away; and

Figures 16and 17 are plan and side elevational views of the core lifter shown in Figures 13-15.

Throughout the drawings corresponding numerals refer to the same parts.

Referring to the drawings, Figure 1, the drillin apparatus consists of a tubular drill rod H! which is fastened by means of coupling I l to the upper end of a drill tube generally designated 12. The drill tube is of larger diameter than the drill rod Ill and is threaded to the coupling H by means of standard drill rod square threads I l. The drill tube [2 extends downwardly and is threaded at 15 (Figure 3) into a reaming shell l6 which may have its outer surface provided with a plurality of set-in chips I! of cutting material such as bort or other suitable abrasive.

The lower end of the reaming shell I6 is threaded at it into the upper part of the bit generally designated 20 which extends downwardly and is thickened at the cutting edge 2|. The outer, lower and inner surfaces of the bit have set-in cutting materials such as bort or other suitable abrasive as indicated at 22 and may be provided with a plurality of water channels 23, as indicated in'Figures 3 and '7. The water channel 23 extends from the inner surface 24 of the bit across the face of the bit and thence upwardly along the outside'of the bit as indicated in Figure 7.

The bit is provided with an inner shoulder 26 to receive a lifter wedge 21 which nests into the drill and has an inner conical surface 28 sloped for cooperating with a core lifter generally designated 30. In Figure 3 the core lifter is of the type illustratedin Figures 9 and 12 and consists of a metal band 3| which is split at one place in its circumference as indicated at 32. The outer surface 33 .is conical to fit the surface 28 of the wedge 21 and the inner surface of the lifter is provided with a plurality of inwardly extending lands or ridges 34 which extend through correspondingly arranged slots 35 in the core barrel inner tube .38. The lower edges of the lands 534 are .chamfered off as indicated at 34A. The inner tube138 extends upwardlyas illustrated in Figures 4A-6A and is seated into a fitting 39 which is in turn threaded as indicated at 40 (Figures -3 and 4) onto the core barrel pivot shaft 4 I.

Referring to Figure 2 the coupling H is internally threaded as indicated at 42 and to the threaded aperture there is attached a valve casing and core barrel suspension member generally designated which is apertured at 45 so as to permit the'flow of drilling fluid such as water therethrough. The member 43 has an outer cylindrical wall andrconstitutes the outer shell of a valve vfor shutting off the flow of drilling fluid. Into the lower end' of themember there 5 is threaded a collar 46 which serves as a bottom limit support for a pair of ball thrust bearings as indicated at 4? in Figures 4-6. The shaft 4| of the core barrel passes through the collar 46 and has a portion of reduced diameter at 48 which is attached to the ball bearing assembly 41 and is held in place by means of a fastening nut 49. The end of the shaft 48 has a ball shaped recess to support a thrustball 50, the upper surface of which presses against the lower end of a valve plug generally designated 52. The valve plug is of generally cylindrical configuration to be described more completely hereinafter, and slides up and down in an elongated cup-shaped valve cylinder liner generally designated 53, the latter being seated against the upper inner surface of the valve casing 43-44.

The valve liner 53 is shown in Figure 10. ,It is closed across its upper surface 54 and this surface has on it a plurality of spaced upwardly extending projections 55 which serve to space the surface 54 from aperture 45, and thus permit the passage. of drilling fluid downwardly between the projections as hereinafter described. The upper portion 57 of the cylindrical valve liner 53 is of reduced diameter such that it leaves a narrow space 58 (Figures 4-6) between its outer surface and the inside of member 44, thus permitting the drilling fluid to pass downwardly.

At 59, however, the valve liner is of a diameter such that it fits snugly into the member 44, thus walling off the flow of drilling fluid at this point. However, a plurality of apertures 55 are provided immediately above the portion 59 and the drilling fluid hence enters the interior of the liner at this point, whence it passes downwardly through groove l2 as later explained. At 62 there is a second spaced portion on the valve liner of sufficient diameter that it fits neatly in the member 44, and in the intervening circumferential groove 53 there are likewise a plurality of apertures 54. Again at the bottom of the valve liner there is a third enlargement as indicated at 55 which likewise fits neatly against the walls of the member 44 and in the wide intervening groove 51 there are provided vertical slots as indicated at 65 for a purpose hereinafter described. The liner 53 is pressed into member 44 and fits sufliciently tightly so as to resist movement during operation of the apparatus, al- I though it can be removed with suitable tools for repair or replacement.

The valve plug 52 is best illustrated in Figures 4, 5 and 6 in which it will be observed that throughout the major portion of the length of plug 52, the diameter is of such a size as to fit neatly into the smooth uniform diameter inner bore of the valve liner 53. The plug 52 is provided with an annular groove at 68 which is connected by means of a port 55 to a central longitudinal aperture l which extends to the upper end of the plug. Further up the valve plug is provided with a wide annular groove as indicated at 12 and the portion 13 of the plug (which defines the upper limit of groove 12) is of such a slightly reduced diameter that a passageway is provided between its outer diameter and the inside of the valve liner 53. Above the portion l3 there is an extending nipple portion 14 and around this there is nested a coil spring F5. The upper end of spring l abuts against contact with ball 58 which is in turn held in place by shaft 48. The force ofspring on shaft 48 6 is transmitted through nut 49 to bearings 4'! until they bottom on the collar 46 which thus defines the limit of downward movement.

The flow of drilling fluid depends upon the drilling conditions and the position of the core barrel and the valve plug 53 which will now be described.

It will be assumber in the first instance that the ground formation being drilled is comparatively durable and that accordingly a core lifter of the type shown in Figures 3, 6A, 9 and 12 is provided. Referring to Figures 4 and 4A there is illustrated a condition in which the drill has been operating for some time and the inner tube 38 has just been filled by a core 85, but it has not yet been lifted to ive the signal to be decribed. During the drilling which is just coming to an end in Figures 4 and 4A, water or other drilling fluid flows downwardly through the passage and outwardly between the projections 55 as indicated by the arrow 3!. The drilling fluid, which is usuall water, then passes in the drilling direction through the annular space between the upper portion 58 of the valve liner 53 and the inside of the valve housing and suspension tube 44 until it reaches the upper row of apertures 60 in the valve cage 53, whence the drilling fiuid flows inwardly into the annular groove 12. Here the new divides, the major portion flowin in the drilling direction through groove '12 and then outwardly through the apertures 64 of the valve liner 53 as indicated by the arrow 82. It will be noted that the apertures 65 extend into the annular groove 53 and that the groove is in registry with a plurality of apertures 83 in the supporting member 44. The flow of drilling liquid continues out through the aperture 83, thence again in the drilling direction, as shown by arrow 85 in the space between the tube 44 and the inner wall of the drill tube l2, thence in a continuation of this space between the inner tube 38 and the drill tube, reaming shell l6 and thence, as indicated by the arrows 8B, Figure 4A, around the outside and inside of the core lifter 30 which at this time m in the raised position gripping the core 85, as shown in Figure 4A, through the space between the core lifter so and wedging member 21, thence in the drilling direction around and under the lower edge 81 of the tube 38 and continuing in the direction of drilling along the inner bit surface 88, Figure 3, thence across the face of the bit or through the bit groove 23, if used, and thence opposite to the drilling direction through the space between the bit and the wall of the hole or the outer portion of the bit groOVe 23, Figures 3 and 7, and up around the bit reaming shell and drill tube to the surface.

The ridges 34 on the core lifter 30 are of such a size that they project through the slots 35 in the inner tube 38, Figure 3, and due to the springiness of the split lifter, the ridges grip against the outer surface of the core 85 which is produced by the drill. In so gripping the core they reach through slots 35 and serve as an anchor which prevents the rotation of the inner tube 38. The spring 15, Figures 4-6, is of sufficient strength that the force transmitted by it downwardly through the valve plug 52, ball 55, shaft is and thence through shaft 4| to the inner tube 38, slots 35 to the lifter 3B, is sufficient to push the core lifter in the drilling direction as the bit progresses. Hence, the core lifter 35 remains in the upper part of the slots 35 in the inner tube 38 (as shown in Figure 4), since it is being pushed downwardly by the upper part of these slots. This condition of operation continues and the core gradually fills the inner tube 38 until it reaches the osition shown in Figure 4A and then as drilling continues a little further, the core pushes up against the inner surface of member M at the top of inner tube 38 and transmits the thrust through the ball 50 to the valve plug 52, causing it to be raised from the position shown in Figures 4-4A to the position shown in Figures -5A. As the valve plug 52 moves through the first part of this lift, it interrupts the flow of fluid at port 54 and thus shuts off the major flow of fluid to the bit. The movement of the tube 33 due to core thrust may continue, however, beyond the position at which port 64 is closed, until spacing collar 39 above the ball bearings 4'! abuts against the lower edge of the valve liner 53.

The shut-oil of flow through port 64 causes a rise in pressure of the drill fluid which is indicated at the operators pressure gauge and the operator is thus provided with a signal telling him that the inner tube 38 has moved and is presumably full. The same indication will be given if the inner tube 38 has become blocked prior to filling, as hereinafter stated.

It will be noted that the movement of the plug 52 responsive to the core pressure is not blocked by fluid trapped in the closed space in valve liner 53 above the plug 52 because the fluid in this space is relieved around the collar l3 and thence through the annular space 12 to the inlet ports 80 and is also relieved through the central aperture to the outgoing stream via ports 63 and 9|. Hence, the valve plug 52 is free to move and compress spring 15.

The incoming stream of fluid through port 80, Figure 4, is mostly shut off when the port 83 is closed as in Figure 5, but some fluid fiows upwardly around the collar 13 as indicated by the arrow 90 and thence downwardly through the central bore 10 of the plug 52 and out through the passageway 69 to annular chamber 68 which communicates through the elongated slots 66 to the elongated annular chamber 61 and from the latter annular space through the ports 9| in the member 44. From this point the flow continues as previously described in the drilling direction around the inner tube 38 to the bit. This flow takes place while the drilling is in progress (Figure 4) and continues after the main flow through ports 64 is shut off as shown in Figure 5. The reduced amount of drilling fluid which is permitted to pass in this manner when the parts are as shown in Figure 5 is considerably less than that normally flowing to the drill surfaces during drilling. This is due to the metering effect of the small space between the outer surface of collar 73 and the inner surface of the valve liner 53 and also due to the metering effect of bore 70 and orifice 69 in the valve plu 52 through which the flow must pass. The reduced amount of drilling fluid is suflicient, however, to prevent burning of the bit during the time interval between the time that the inner tube 38 is moved responsive to core pressure and actually shuts off the flow to initiate the signal and the time this function is reflected on the operators pressure gauge and the operator has a chance to stop the machine. It may be noted parenthetically that the drilling fluid pumped to the bit usually contains a certain amount of air which, due to its compressibility, delays to a variable degree the rise in pressure occasioned by the closure of the port '54. Hence, even though the signal given to the operator may be somewhat indistinct or delayed by the com- 8 pressibility of the contained gases in the drilling fluid, a small amount of fluid nevertheless is conducted to the bit, and this serves to prevent burning of the bit.

After rotation of the bit has been stopped the operator withdraws the bit, as illustrated in Fisures 6-6A. When this occurs the drill tube first rises and then when bearings 41 bottom upon collar 46 the inner tube 38 assembly is also withdrawn. The gripping action of the core lifter surfaces 34 upon the core causes it to be held in place as the bit is moved upwardly, and consequently the wedging surface 21 (which is carried by the bit) is brought upwardly into contact with the outer cooperating wedging surface 33 of the core lifter. This causes the core lifter 30 to be contracted and the lands 34 to be gripped ever more tightly onto the core until the core is snapped off at the core lifter. Hence, as the drill is drawn upwardly it breaks off the core along the line 93 of Figure 6A and the core thus held in the core barrel is drawn to the surface whence it can easily be released by the operator.

It will be noted that in so doing the core barrel 38 is permitted to be pushed down under the action of spring 15, thus returning the valve plug 52 to its original condition in which the flow of drilling fluid from aperture 45 occurs via arrows 8|, through aperture GI! and along the path of arrow 82, thence downwardly around the core barrel to the bit surface, as previously described. This permits the liquid in the long drill rod to drain out as the drill rod is lifted, thus obviatin a wet pull and hence obviating the lifting of a fluid loaded, difficultly handled drill rod.

When the drill enters into crumbling formation of the type shown in Figure 11 the breakage of the produced core causes it to produce an expanded irregular outer surface as shown in Figure 11, which serves to raise the core barrel and hence immediately to signal to the operator that a jamming has occurred. When this occurs the operator draws the drill rod as previously described, removes the core lifter 30 and inserts in its place a core lifter of the type shown in F ures 13-47. The core lifter shown removed in Figures 16 and 17 consists of a cylindrical tube generally designated 95 which is provided with inwardly extending tabs 36 at its upper surface which are aligned with and abut against the upper ends of slots 35. The bent over tips 86 serve to engage upon the upper end of the slot, thus preventing movement of the core lifter tube 95 upwardly beyond the position shown in Figure 15. The inner surface of the tube 95 is of a diameter such that it slides freely up and down on the lower end of the core barrel and it is provided with a plurality of spring fingers 98 which may be of any degree of resiliency desired for gripping cores of varying friability. The fingers 98 are positioned so as to extend through the slots 35 and into contact with the core produced by the drill. The springiness of the fingers 38 may be very slight or heavier depending upon the hardness of the ground structure being drilled. As the drill progresses in drilling direction, as shown in Figure 14, the upper portion of the slots 35 of the core barrel 44 rests against the portion 96 of the tube 95 causing it to be pushed downwardly on the core. The fingers 98 are in the meantime pushed outwardly by the core to the position shown in Figure 14 and grip the core lightly or heavily depending upon the resiliency of the fingers 98, thus preventing rotation of the tube and hence likewise preventing rotation 9 of the inner tube 38. This serves to protect the core even though it is very fragile.

The flow of fluid during the drilling run is as described with reference to Figure 4. When the core has filled the core barrel 38 or if a blocking should occur such as to cause the core to grip the sides of the core barrel, it is raised to the position shown in Figure 5, and the flow of drilling fluid is mostly shut off and a signal provided to the operator. A small amount of fluid, however, does continue to flow via arrows 90, drill hole and arrow 90 as previously described. The operator then shuts down and raises the drill rod as shown in Figure 15. The collar 95 is held to the core by means of the fingers 98. Hence, the first action is simply to draw the drill tube from the hole, and when bearin 4'! rests upon collar 46 the core barrel is likewise lifted. The collar 95 meanwhile stays in place and finally the lower edge of the collar abuts against the shoulder 26 of the bit. Then as the drill is raised the collar 95 is lifted and the core is broken off and held in the core barrel as shown in Figure and is carried to the surface as the operator lifts the drill rod.

It will be noted that in moving from the position shown in Figure 4 to the position shown in Figure 5, the first motion of plug 52 is to close off port 64, but that the plug is thereafter free to move a very considerable distance until finally the collar 99 around nut 49 and ball 50 rises into contact with the lower surface Illl of the valve liner 53. This is important because in deep holes there is a long column of water from the bit to the pump. This column usually contains a certain amount of air which, because of its compressibility, will not permit an immediate pressure rise in the pump after the core blocks and the valve closes. I have found that if the bearing carrying the core barrel is constructed so as not to have any movement beyond the valve closing to pieces is preserved. In addition there is a distinct saving in wear and breakage of the apparatus.

In use the apparatus of the present invention has permitted the recovery of substantially 100% of core in broken formations where previously 10 recovery was the best that could be obtained.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein except as defined by the appended claims.

What I claim is:

1. A core barrel drill comprising a tubular drill member having a drilling surface at the end thereof and an axial fluid passage therethrough; valve means in said passage for controlling the flow of fluid therethrough; said valve means including a valve casing member fixed to the tubular drill and having a fluid inlet port, a main outlet port, a bypass outlet port and passageways communieating between said inlet port and said outlet and bypass ports; a valve plug member having a bypass therein communicating between said inlet port and said bypass outlet port, said valve plug I have 10 member being movable axially in respect to said valve casing member; and a core ibarrel rotatably connected to said valve casing and being adapted for axial movement with respect thereto for moving said Valve plug member to close the passageway communicating between said inlet port and said main outlet port and bypass fluid around said valve means whereby a portion of the fluid is conducted to the drilling surface when said m in outlet port is closed.

2. A core barrel drill comprising a tubular drill having a drilling surface at the end thereof having an axial fiuid passageway therethrough; valve means in said passageway for restricting but not completely stopping the flow of fluid therethrough, said valve means including a tubular valve casing of smaller diameter than the tubular drill axially disposed therein and affixed at one end thereof to said tubular drill so as to rotate therewith; a valve liner axially disposed within said tubular valve casing and having an inlet port, a main outlet port and a bypass port; a valving plug slidably mounted within said valve liner and having a bypass therein communicating with said bypass outlet, said valving plug being adapted selectively to connect said inlet port and said main outlet port or close said main outlet port; spring resilient means disposed between said valve liner and said valving plug adapted to urge said liner and said plug apart to open said main outlet port; and a core barrel inner tube rotatably supported on the free end of said valve casing and adapted for axial movement with respect to said casing to exert pressure upon said valving plug to overcome the pressure exerted by said resilient member between said liner and said plug and move said valving plug within said valve liner to close said main outlet port.

3. A core barrel drill as set forth in claim 2, characterized in that said valving plug is provided with a bypass having a restricted orifice therein and an annular horizontally disposed projection on the surface thereof forming a restricted fluid passageway between said valving plug and said valve liner.

4. A core barrel drill as set forth in claim 2 characterized in that the said valve liner is provided with an axially disposed elongated bypass port to permit extensive axial movement between said valving plug and said valve liner without causing said bypass port to be closed by said valving plug and a stop member disposed between said core barrel inner tube and said valve liner adapted to prevent said core barrel inner tube from exerting sufiicient force upon said valving plug to cause relative axial movement between said plug and said liner which would result in said valving plug closing said bypass outlet in said valve liner.

ALBERT F. PIC'KARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 374,819 Ball Dec. 13, 1887 643,082 Bullock Feb. 6, 1900 1,830,681 Scott l Nov. 3, 1931 2,313,576 Phillips et al Mar. 9, 1943 2,422,955 Duffield June 24, 1947 FOREIGN PATENTS Number Country Date 118,835 Australia Aug. 16, 1943 

